Source:http://linkedlifedata.com/resource/umls/id/C0066029
NCI: A spironolactone derivative and aldosterone antagonist with diuretic activity. Mespirenone, after in vivo metabolization, inhibits aldosterone synthase (steroid 18-hydroxylase), thereby preventing the synthesis of aldosterone in addition to the synthesis of other mineralocorticoids. The blockade of aldosterone synthesis results in increased sodium and water excretion while reducing potassium excretion within the kidney. Mespirenone has a short half-life and is metabolized completely into active metabolites.